The main objectives are to study the mechanisms controlling heme biosynthesis and biochemical and clinical aspects of the porphyrias, and to apply the knowledge gained from the above objectives to the study of tumors and tumor-host relationships as well as primary diseases of porphyrin metabolism. BIBLIOGRAPHIC REFERENCE: Lamon, J.: Clinical aspects of porphyrin measurements other than lead poisoning. Clin. Chem. 23: 260-263, 1977.